Add poseidon hash type

encoding.go

@@ -6,6 +6,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/wealdtech/go-merkletree/v2/blake2b"
 	"github.com/wealdtech/go-merkletree/v2/keccak256"
+	"github.com/wealdtech/go-merkletree/v2/poseidon"
 	"github.com/wealdtech/go-merkletree/v2/sha3"
 )
 
@@ -49,6 +50,8 @@ func (t *MerkleTree) UnmarshalJSON(data []byte) error {
 		aux.Hash = blake2b.New()
 	case "keccak256":
 		aux.Hash = keccak256.New()
+	case "poseidon":
+		aux.Hash = poseidon.New()
 	default:
 		return errors.New("cannot parse hash type")
 	}

go.mod

@@ -4,12 +4,15 @@ go 1.20
 
 require (
 	github.com/pkg/errors v0.9.1
-	github.com/stretchr/testify v1.3.0
+	github.com/stretchr/testify v1.8.2
 	golang.org/x/crypto v0.18.0
 )
 
+require gopkg.in/yaml.v3 v3.0.1 // indirect
+
 require (
-	github.com/davecgh/go-spew v1.1.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/iden3/go-iden3-crypto v0.0.16
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/sys v0.16.0 // indirect
 )

go.sum

@@ -1,13 +1,26 @@
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/iden3/go-iden3-crypto v0.0.16 h1:zN867xiz6HgErXVIV/6WyteGcOukE9gybYTorBMEdsk=
+github.com/iden3/go-iden3-crypto v0.0.16/go.mod h1:dLpM4vEPJ3nDHzhWFXDjzkn1qHoBeOT/3UEhXsEsP3E=
+github.com/leanovate/gopter v0.2.9 h1:fQjYxZaynp97ozCzfOyOuAGOU4aU/z37zf/tOujFk7c=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
 golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
 golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
 golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

poseidon/hash.go

@@ -0,0 +1,61 @@
+// Copyright © 2019 Weald Technology Trading
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package poseidon provides hashing using the Poseidon system.
+package poseidon
+
+import (
+	"github.com/iden3/go-iden3-crypto/poseidon"
+)
+
+const _hashlength = 32
+
+// Poseidon is the Poseidon hashing method.
+type Poseidon struct{}
+
+// New creates a new Poseidon hashing method with `frameSize` set to 16.
+func New() *Poseidon {
+	return &Poseidon{}
+}
+
+// Hash generates a Poseidon hash from a byte array.
+func (ph *Poseidon) Hash(data ...[]byte) []byte {
+	var hash []byte
+	if len(data) == 1 {
+		hash = poseidon.Sum(data[0])
+	} else {
+		concatDataLen := 0
+		for _, d := range data {
+			concatDataLen += len(d)
+		}
+		concatData := make([]byte, concatDataLen)
+		curOffset := 0
+		for _, d := range data {
+			copy(concatData[curOffset:], d)
+			curOffset += len(d)
+		}
+		hash = poseidon.Sum(concatData)
+	}
+
+	return hash
+}
+
+// HashLength returns the length of hashes generated by Hash() in bytes.
+func (ph *Poseidon) HashLength() int {
+	return _hashlength
+}
+
+// HashName returns the name of this hash.
+func (ph *Poseidon) HashName() string {
+	return "poseidon"
+}

poseidon/hash_internal_test.go

@@ -0,0 +1,24 @@
+// Copyright © 2023 Weald Technology Trading.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package poseidon
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHashLength(t *testing.T) {
+	assert.Equal(t, _hashlength, New().HashLength(), "incorrect hash length reported")
+}

poseidon/hash_test.go

@@ -0,0 +1,75 @@
+// Copyright © 2018, 2019 Weald Technology Trading
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package poseidon_test
+
+import (
+	"encoding/hex"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/wealdtech/go-merkletree/v2/poseidon"
+)
+
+// _byteArray is a helper to turn a string in to a byte array
+func _byteArray(input string) []byte {
+	x, err := hex.DecodeString(input)
+	if err != nil {
+		panic(err)
+	}
+	return x
+}
+
+func TestHash(t *testing.T) {
+	tests := []struct {
+		data   []byte
+		output []byte
+	}{
+		{
+			data:   _byteArray("e9e0083e456539e9f6336164cd98700e668178f98af147ef750eb90afcf2f637"),
+			output: _byteArray("05c26e4fd0b4cbf27aa04a2f7934afc086bfb20e9d431f7c50b7e5cc5ea07a02"),
+		},
+	}
+
+	hash := poseidon.New()
+	assert.Equal(t, "poseidon", hash.HashName())
+	for i, test := range tests {
+		output := hash.Hash(test.data)
+		assert.Equal(t, test.output, output, fmt.Sprintf("failed at test %d", i))
+	}
+}
+
+func TestMultiHash(t *testing.T) {
+	tests := []struct {
+		data1  []byte
+		data2  []byte
+		data3  []byte
+		data4  []byte
+		output []byte
+	}{
+		{
+			data1:  _byteArray("e9e0083e456539e9"),
+			data2:  _byteArray("f6336164cd98700e"),
+			data3:  _byteArray("668178f98af147ef"),
+			data4:  _byteArray("750eb90afcf2f637"),
+			output: _byteArray("05c26e4fd0b4cbf27aa04a2f7934afc086bfb20e9d431f7c50b7e5cc5ea07a02"),
+		},
+	}
+
+	hash := poseidon.New()
+	for i, test := range tests {
+		output := hash.Hash(test.data1, test.data2, test.data3, test.data4)
+		assert.Equal(t, test.output, output, fmt.Sprintf("failed at test %d", i))
+	}
+}